Field
Implementations described herein generally relate to polishing articles and methods of manufacturing polishing articles used in polishing processes and cleaning processes. More particularly, implementations disclosed herein relate to composite polishing articles having graded properties.
Description of the Related Art
Chemical-mechanical polishing (CMP) processes are commonly used for planarization of substrates during fabrication of semiconductor devices. During CMP processing, a substrate is mounted on a carrier head with the device surface placed against a rotating polishing pad. The carrier head provides a controllable load on the substrate to push the device surface against the polishing pad. A polishing liquid, such as slurry with abrasive particles (e.g., silica (SiO2), alumina (Al2O3), or ceria (CeO2)), is typically supplied to the surface of the polishing pad.
As feature sizes decrease, planarization of both the front layers and the back layers by CMP processes becomes more critical. Unfortunately, byproducts of the CMP process, for example, abrasive particles and metallic contaminants generated during the CMP process may damage the surface of the substrate. In cases where abrasive polishing slurries are used, these abrasive particles may originate from the polishing slurry. In some cases, the abrasive particles may originate from the polishing pad. Additionally, abrasive particles may originate from the polished surface materials of the substrate and the polishing equipment. These particles may physically attach to the surface of the substrate due to the mechanical pressure generated by the polishing pad. Metallic contaminants arise from the abraded metal lines, metal ions in slurries, and the polishing equipment. These metallic contaminants may embed in the surface of the substrate and are often difficult to remove using subsequent cleaning processes. Current polishing pad designs and post-polishing cleaning processes often yield polished substrates suffering from defects caused by the byproducts of the CMP process.
Therefore, there is a need for a polishing article that provides an improved polishing process with reduced defects and methods for making the improved polishing pad.